Pros
For a public company, this is an incredibly transparent organization (I've never seen anything quite like this before). I've also found many kindred spirits on my new team: people are passionate about their work; they have all been super helpful / friendly; and there's great energy here! Everyone is constantly encouraged to act boldly (and when I've seen a few people do so, they were applauded for it). There has been absolutely no spin doctoring on anything so far (and I'm the kind of person who really watches out for this one). Even though I'm still relatively new to Twitter, I already feel like I have a "voice" here: I've been able to push new ideas forward--and I've been encouraged to keep it up! Twitter continues to create transformative technology that truly makes the world a better place, and I'm proud to now be a part of that. Twitter also creates a lot of industry standard in technology and openly shares its innovation with the open source community, which I really like/admire.
Cons
Coming from a start-up environment (we were recently acquired by Twitter), things tend to move a bit slower in some regards Communication between the teams could be improved